Question

We are planning a new embedded board that must run custom Linux software we’ve developed. Our current platform uses the 2.6.32 kernel, Debian Lenny on an x86. We do not have any custom hardware and all interfacing at the moment is via serial ports. I’ve been looking TI AM355x chip, but it doesn’t look like they have their Linux SDK ready yet. There is also the BeagleBone, but that appears to not have any official TI support, the earliest kernel is 3.0 and they are running Debian Wheezy.

Can anyone recommend a well supported ARM CPU that can run the 2.6.32 kernel with Debian Lenny? By well supported I would want something that is supported in the mainline kernel, is backed by a company with good commitment and history of Linux support, and has paid support options.

I know this is a bit general but hopefully someone can respond with vendors to look at & vendors to definitely avoid?

TY,
Fred

Answer 1

I think you are putting the cart before the horse here. I would recommend choosing the platform first and then worry about the operating system afterwards. Be aware even with the same kernel and user-space versions from the same vendors, there are significant differences between x86 and ARM systems – particularly in terms of power management and drivers.

Kernel version 2.6.32 is also pretty old – in fact ancient in the fast moving world of ARM SoC. New functionality tends not to be backported.

In terms of best supported ARM SoCs at least the following are factors:

• A particular kernel tree (almost never main-line) supports all of the functionality of the ARM SoC
• [Paid for] Commercial or vendor support is available for the SoC
• Wide choice of COTS systems available using SoC.
• Full system support in OS distributions
• Supported by developer/enthusiast community

Taking Pandaboard as a case study since it’s been mentioned by several other posters:

• Most device functionality is supported in recent mainline distros
• Wide community support – although very little of the documentation is authoritative or maintained and answers can be hard to find. You’ll be on your own if you get stuck.
• You can’t buy Pandaboard for production use, it’s sold as a evaluation board with little vendor support.
• You can’t buy Pandaboard in volume.
• TI don’t provide support for OMAP4 unless you’re a tier 1 OEM, although most of the datasheet (7k pages, 44MiB) is public. Other parts under NDA.

It’s fairly clear from your description that this doesn’t fit your needs. I would therefore suggest looking at COTS systems.

I’ve had good experience using products from PhyTec, who make a number of different ARM SoC-based systems (in some cases, on interchangeable modules). They ship their systems qualified with Pengutronix’s Linux Distro, although there’s nothing to stop you using their kernel and somebody else’s user-space (I used Angstrom). PhyTec’s kernel patches are contributed to the linux-omap tree. [5]

There are plenty of other vendors of similar COTS systems.

Needless to say, these COTS board are not directly supported by mainline distros, although in practice are fairly close.

[5]: Linux mainline is worth avoiding for ARM SoC.